Formula:
Y=Mx+b
(Basically its like this: Y=Slope(x)+Y intercept)
The M will always be slope, and the b is always going to be the y intercept.
So, all you have to do now is find them.
y=-4x-9
y=-4(slope)x-9(y intercept)
So, -4 is the slope, and the y intercept is -9
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~Hope this helped :)